Chitosan-based biopolymers for radioprotection: Mechanisms and biomedical applications in radiotherapy — A review

Ionizing radiation (IR) plays a crucial role in medical diagnostics and cancer therapy, yet its non-selective nature often causes serious damage to healthy tissues. The resulting oxidative stress, inflammation, and DNA injury underline the urgent need for safe and efficient radioprotective agents. Chitosan (CTS), a natural polysaccharide derived from chitin, has recently gained attention as a promising biomaterial for radiation protection. Its biocompatibility, biodegradability, and versatile biological activities, especially antioxidant, anti-inflammatory, immunomodulatory, and metal-chelating properties, make it particularly attractive for biomedical applications. This review summarizes current knowledge on the structural features, extraction methods, and physicochemical parameters of CTS that influence its biological performance under irradiation. It discusses the main mechanisms underlying its radioprotective action, including free-radical scavenging, stabilization of DNA, modulation of cytokine release, and acceleration of tissue repair. Special emphasis is placed on recent advances in CTS-based systems such as nanoparticles, hydrogels, and 3D-printed biomaterials that improve the delivery and efficacy of radioprotective agents. Although several studies demonstrate encouraging results both in vitro and in vivo, further work is needed to standardize CTS production, optimize formulations, and confirm clinical safety. Altogether, CTS emerges as a multifunctional and sustainable polymer with strong potential to shape the next generation of natural radioprotectors.